This invention relates to automatic bale wagons, that is bale wagons which pick up bales from the ground, load the bales onto one or more load beds or floors in a predetermined manner, and unload the bales, also in a predetermined manner, without any manual assistance save for an operator to drive the wagon (be it of the self-propelled or towed type) and operate the controls.
In contrast to the automatic bale wagon, there exists the random bale wagon which has the advantage of simplicity, since all that is required is a load space and a mechanism to pick-up bales from the ground and throw them into the load space, but suffers from the disadvantage that maximum use is not made of the load space due to the random loading of the bales therein unless there is manual intervention which is time-consuming. Thus the automatic bale wagon was developed to maximise the use of the available load space and to minimise the time required for bale loading and unloading.
Different types of automatic bale wagons have been proposed and a particularly successful type has been the one employing a load table onto which are transferred bales from a transfer table receiving bales from bale pick-up means, the load table being generally horizontal during the loading operation. When the load table is full of bales, it is pivoted to a generally vertical position so that the bales thereon form a tier of bales which is then moved onto a load bed or floor of the bale wagon. As tiers of bales are successively placed on the load bed, a stack of bales is formed which is compact and, therefore, maximum use is made of the available load space. A bale-unloading mechanism is provided which unloads bales either singly or otherwise.
Another type of automatic bale wagon employs a plurality of load floors disposed one above the other and various mechanisms for loading the floors with bales either in turn or simultaneously. In German Patent Specification No. 2,352,208 there is disclosed a bale wagon of this type in which each load floor, except the lowermost, is provided with a conveyor which also serves to transfer bales from one floor to another in conjunction with passive guide means. The use of a conveyor on all but one load floor increases the cost of production and maintenance of the bale wagon and the passive guide means are unsatisfactory in that if they are dimensioned so as to exercise close guidance of the bales, as is desired, then there is inevitably considerable sliding contact between the bales and guide means which gives rise to friction resulting in hesitant bale movement. If sliding contact between the bales and guide means is minimised, there is some loss in bale control with the attendant risk of bale jamming.
Another example of this type of bale wagon is to be found in British Patent Specification No. 1,453,218 which discloses one arrangement having a conveyor associated with each load floor and employing a bale elevator at each end of the wagon in the form of an endless conveyor operable to transfer bales from one floor to another. The use of active conveyors avoids the aforementioned problems associated with passive guide means but increases the number of complicated, and hence expensive, components. Furthermore, the elevators do not exercise positive control over the bales so that hesitant bale movement can arise which is undesirable. In another arrangement disclosed in British Patent Specification No. 1,453,218, only alternate load floors are provided with conveyors, which is a useful saving, but the bale elevators are replaced by rotary, transversely-extending bale conveyors which act in association with passive guide means to transfer bales from one load floor to another. These extra conveyors negate the saving in the floor conveyors and the problems arising from the use of passive guide means are present.